Authorities said that homes were evacuated in the Southern California desert town of Mecca for a mile where a train derailed and spewed toxic gas early Tuesday.

A part of a Union Pacific train went off the tracks before 9 p.m. Monday and about 60 residents were not allowed to return to 40 homes.

According to James Barnes, the railroad's director of media information, 29 cars out of the 65-car train that was heading from Colton to El Centro went off the track.

He said that six of the cars were upright and 23were “in a pile.” There were no injuries reported.

It wasn’t clear why the train derailed.

Initial reports were saying that two tanker cars were on fire. According to Barnes, some wooden rail ties were on fire.

Riverside County fire Capt. Julie Hutchinson said that from four tanker cars liquid hydrochloric and phosphoric acid were leaking.

Due to the acid a 25-foot plume was sent up Monday night.  

On Tuesday morning a smaller plume, triggered from acid reacting with organic material, was still hovering at the scene of the accident. Hutchinson said that it didn’t represent a public health threat.

According to Barnes, the phosphoric acid was reacting with the soil.

He said: "It's kind of like a smoldering," the Associated Press reports.

Until the acid leaks are stopped, people are being kept out of a mile area around the site of the accident.

Barnes said: "We're in the process of staging the equipment nearby. Right now, the important thing is to make sure the area's safe."

According to him, there were 2,000 feet of damaged tracks and 25 trains were delayed. Some of the delayed tracks were rerouted through Salt Lake City, Utah.

The accident occurred next to Highway 111, which had to be shut down for a seven-mile stretch south of State Road 195.

Mecca is located almost 140 miles southeast of Los Angeles and has almost 5,400 residents.